Otsuka Nao, Guiso Nicole, Bouchez Valérie
Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0002, Japan.
Institut Pasteur, Molecular Prevention and Therapy of Human Diseases, 25 rue du Dr Roux, Paris 75015, France.
Microbiology (Reading). 2017 Sep;163(9):1364-1368. doi: 10.1099/mic.0.000514. Epub 2017 Aug 15.
Bordetella pertussis, a human pathogenic bacterium, produces either one or two types of serologically distinct fimbriae, Fim2 and Fim3, as virulence factors. The expression of fim2 and fim3 is regulated by the BvgAS two-component system and the length of poly(C) stretches in Pfim promoters. In the Bvg+ phase, B. pertussis virulence-activated genes (vags) are up-regulated and virulence-repressed genes (vrgs) are down-regulated. Previous studies have shown that fim2 is a vag, but there is no consensus on fim3 regulation. We examined the regulation of fimbrial expression in B. pertussis clinical isolates. Our findings indicate that fim2 is a vag, while fim3 is a vag when Pfim3 poly(C)>13C, and a vrg when poly(C)≤13C. Although increased fim3 expression was observed in the Bvg- phase in isolates with Pfim3 poly(C)≤13C, Fim3 production was not detected, suggesting post-transcriptional regulation of fim3 expression. These findings provide an insight into the regulation of fimbrial expression in B. pertussis.
百日咳博德特氏菌是一种人类致病细菌，可产生一种或两种血清学上不同的菌毛，即Fim2和Fim3，作为毒力因子。Fim2和Fim3的表达受BvgAS双组分系统和Pfim启动子中聚（C）序列长度的调控。在Bvg+期，百日咳博德特氏菌的毒力激活基因（vags）上调，毒力抑制基因（vrgs）下调。先前的研究表明，Fim2是一个vags，但关于Fim3的调控尚无共识。我们研究了百日咳博德特氏菌临床分离株中菌毛表达的调控。我们的研究结果表明，Fim2是一个vags，而当Pfim3聚（C）>13C时，Fim3是一个vags，当聚（C）≤13C时，Fim3是一个vrg。尽管在Pfim3聚（C）≤13C的分离株中，在Bvg-期观察到Fim3表达增加，但未检测到Fim3的产生，这表明Fim3表达存在转录后调控。这些发现为百日咳博德特氏菌菌毛表达的调控提供了见解。
